In U.S. Pat. No. 3,773,925, there is described and claimed the new antibiotic partricin, in U.S. Pat. No. 3,780,173, there is described and claimed the methyl ester of partricin and in co-pending U.S. patent application Ser. No. 441,988 dated Feb. 13, 1974, there are described and claimed certain alkyl esters of partricin other than its methyl ester.
Although partricin and its alkyl esters have good solubilities in some organic solvents, they are practically insoluble in water, which is a disadvantage since water is the preferred medium for administering drugs by injection.
As a result of our investigations, we found that partricin and its methyl ester form water-soluble complexes with certain surfactants. In co-pending U.S. patent application Ser. No. 469,889 filed May 14, 1974, now U.S. Pat. No. 3,961,048 there is described and claimed a water-soluble pharmaceutical complex comprising partricin and/or partricin methyl ester and at least one anionic and/or cationic surfactant. The only specific examples of such surfactants mentioned in U.S. Pat. No. 3,961,048 are sodium lauryl sulphate, sodium tetradecyl sulphate and benzalkonium chloride. However, the prolonged administration of the sulphate esters of higher alcohols is not always free from danger, particularly when they are injected by the intravenous route; sodium lauryl sulphate, for example, given in high doses and for prolonged endovenous treatments, can exert a toxic effect on the lungs, kidney and liver.
Continuing our investigations, we have now found that partricin and its alkyl esters can be rendered water-soluble by complex formation with sodium desoxycholate and/or sodium dehydrocholate.